Sheet folding machine



March 20, 1951 R. L. SJOSTROM 2,545,793

SHEET FOLDING MACHINE Filed March 16, 1948 1o Sheets-Sheet 1 INVE NTOR. fiobefl' 1. 5705191:

March 20, 1951 R. SJOSTROM SHEET FOLDING MACHINE 1O Sheets-Sheet 2 Filed March 16, 1948 z: wwwflmm mamm n. 5 M DM E m n. 0 M n o 2 E? on Q m mzlw.

March 20, 1951 R. SJOSTROM 2,545,798

SHEET FOLDING MACHINE Filed March 16, 1948 10 Sheets-Sheet 3 F IE. 4.-

INVENTOR.

Ebcr? 1.. 30 m,

BY gum W March 20, 1951 R. SJOSTROM 2,545,798

SHEET FOLDING MACHINE Filed March 16, 1948 0 Sheets-Sheet 4 ECW FIG. 5

3 INVENTOR.

S AMP IQy March 20, 1951 R. L. SJOSTROM 2,545,798

SHEET FOLDING MACHINE Filed March 16, 1948 10 Sheets-Sheet 6 BY yum Ill: Affair/e March 20, 1951 R. L. SJOSTROM SHEET FOLDING MACHINE 10 Sheets-Sheet 7 Filed March 16, 1948 March 951 R. L. SJOSTROM 2,545,798

SHEET FOLDING MACHINE Filed March 16, 1948 '10 Sheets-Sheet s FIE.

\NVENTOR. fiber?" L. S asfrwn BY Won? fla- Affarne March 20, 1951 s os 2,545,798

SHEET FOLDING MACHINE Filed March 16, 1948 10 Sheets-Sheet 9 INVENTO R. 1P0 ba'rl L Qasfrflm BY gum my 59 ,4Horne March 20, 1951 R. SJOSTROM SHEET FOLDING MACHINE l0 Sheets-Sheet 10 Filed March 16, 1948 mm M 2 il w; M m. MM M n M p VI 5 "u ,WMUMIIIIIIHH Patented Mar. 20, 1951 UNITED STATES PATENT OFFICE Robert L. Sjostrom, Andover, Mass.

Application March 16, 1948, Serial No. 15,065

The present invention relates to a machine for folding flexible sheets such as cloth, paper, and fabrics, but finds its particular application in the folding of bed sheets, pillow cases, towels and the like in the textile industry and in folding of laundered clothes, sheets, fabrics, and the like.

In the present invention, the article to be folded is fed by means of a conveyor belt over the folding table wherein plates are moved in from the sides laterally in timed relation to effect a longitudinal fold in the manner that may be' desired. The machine of the present invention may be used to make a single fold, a fold in three sections by means of a longitudinal fold from each side, a three-layer fold by means of a longitudinal fold only on one side, a fold of each side to the center, and many other types of folds as may be desired. Subsequent to finishing the longitudinal folding, which may be accomplished with or without stopping the conveyor belts, the material is conveyed through the rest of the machine wherein lateral folds as desired are made in the material.

In the prior art, the folding is accomplished by means of guiding the edges or sides of the material through channels or guides somewhat in the manner that the hemmer of a sewing machine operates. Here, however, the fold is positively made by actively turning the material by the use of moving elements, particularly plates which operate positively and entirely independently of the feed of the material through the machine. While the machines of the prior art must thread or guide the material in the folding samples, in the present invention the feed to the folding board is a simple straight feed, and all that is necessary is to present the sheet laid out flat as it comes on the folding table. may be accomplished in any way desired although the manner herein illustrated is preferred and has its advantages and the machine can be operated by one operator, if a manual feed is used, or, if an automatic feed is used, one operator can operate a bank of machines. Other advantages and features of the invention will be understood from the description in the specifications below when taken in connection with the drawings illustrating an embodiment of the invention, in which:

Fig. 1 shows a side section in elevation of the forward part of the machine on the line l| of Fig. 2;

Fig. 2 shows a plan view of the same forward end of the machine shown in Fig. 1;

Fig. 3 shows a section taken on the line 3-3 of Fig. l;

Fig. 4 shows a section taken on the line 44 of Fig. 2;

Fig. 5 shows a section taken on the line 5- -5 of Fig. 4;

Claims. (Cl. 27084) The feed Fig. 6 shows a section taken on the line 6--6 of Fig. 5;

Fig. 7 shows a top plan view of the back portion of the machine continuing from the line of Fig.2; Fig. 8 shows a sectional elevation on theline 8-8 of Fig. 7;

Fig. 9 shows a detail of a stop mechanism used to stop the movement of the sheets during the folding;

Fig. 10 shows a detail of switches operated by the mechanism;

' Fig. 11 shows an electric wiring diagram for the operation and control of certain elements in the system;

Fig. 12 shows a modified detail which may be used in the present invention; I

Fig. 13 shows a side elevation of a detail and; Fig. 14 shows a front elevation of the same detail.

The machine has an elongated frame I (as indicated by Figs. 1 and 2) of general rectangular section. At the left end of the machine '(as viewed in Figs. 1 and 2) there is mounted'on the frame a roller 2 carried by'a'shaft 3 extending laterally across the frame and ournalled at bearings 4, 4 at each side. The central portion of this section of the machine is provided with a plate 5 which extends up to the roller 2 but is lower than the top tangential surface; 'In a plane above the surface of the plate '5, ateither 'side thereof, is a group of comparatively narrowconveyor belts 6, 6, 6, etc. on one 'sideand' "l; l, 1, etc. on the other side. These conveyor belts form a conveying surface slightly above that'of' the plate 5. The conveyor belts pass over a second roll 8 and return to the roll 2, the conveyor belts moving in the direction shown by th'e'arrow 9. Before the position of the second rouera; a supporting stand it is mounted on the frame I. This supporting standard is provided with a cross brace or bridge II having a flat flange or shelf l2, on Which spring fingers !3,' I3, etc., and l3", [3, etc., are mounted. These spring fingers are located between the conveyor belt strips, preferably between each of the belt strips. 'Ihey are further sloped upwards to a point at M sufliciently'high to deliver the material or sheet in the section where'the fingers are on the plates i5 and it. The fingers I 3 raise the material sufficiently to permit it to slide over the plate 86, while the fingers I3 permit the other section of th material to slide over the plate' I5. The plates l5 and It, as will be seen later, are at different levels.

Between the normal side positions of the plates l5 and I6 and at a lower level than either is a central plate H which is supported from the bridging frame I8. This bridgingframe, as in dicated in Fig. 1, may be formed as a part of the supporting standard l0, and comprises averroller 26 and returning to roller 8.

tically positioned cross plate I9 with a horizontal plate 20, forming a right angle element, both extending across the entire frame of the machine. The horizontal plate 29. carries the light source 24; of a. photo electric system, which will be explained later. The vertical cross piece I!) has attached to it one end 22 of the plate H,

which is curved upwards from the fiat portion of the plate as is indicated by the section 2.3. The material of the plate is sufficiently thin and has sufficient spring therein so that the flat section of the plate hangs flexibly from its support. The plate I? bears by its own weight lightly on a centrally positioned conveyor belt 24, which at the forward section of the machine is wrapped about the roller 8' (see Fig. 1). between the sections where the narrow conveyor belts are positioned. The belt 24 extends in the opposite direction, however, from the conveyor belts 6 and I, but moves in the same direction as the strips 6- and 'I as indicated by the arrow 25. The belt 24 is a continuous belt passing about a second The plates I5, [6, and I! are preferably: of the same length or nearly the same length and the material as it comes from these plates passes over the top surface of the plates I and I5 and beneath the lower surface of the plate I'I lying in frictional contact with the belt 24. When the material has been brought to the beginning of the plates I5,

1 6, and IT, the belt 24', moving at the same speed approximately as the belt strips 6 and I, contin-ues. to carry the material along the machine. When both the forward and the rear edges of the material are on the plates I5, I6, and H, the plates I5 and. [6 move laterally fromthe sides ina manner which will presently be described to accomplish the. folding of the sheet. As indicated: more fully in Figs. 4, 5, and 6, the spring pivoted plate I1 is at the lowest level, the plate I5 being at the next level, and: the plate IE at the top level. The plate I5 is reinforced by a cross bar 21 attached to the plate I5 and extending in a longitudinal direction of the machine. This plate at its end carries two bearing sleeves 28 and 29, which have a good sliding fit on the cross rods. 39 and 31 supported at their ends to the frame l of the machine. By means of this mounting, the plate I5 may move laterally part way, substantially to the center or beyond the center of the machine within wide limits of motion. The plate I6 is similarly supported by means of bearing sleeves 32 and 33 on the same rods 3!]. and 3Ii, the bearing sleeves being in each case at the extreme side so that in the motion shafts; Fig. 4,. 34 and 35 which are driven in the correct phase for the desired operation as will be explained later, are permanently attached to :the crank arms 36' and 3"! respectively, which .crank arms form the first of a pair of links pivoted to the tables respectively; The arm 31- is pivoted at 38' to the link 39-, which at its other end ispivoted in. the piece 40 attached beneath the plate Similarly, the arm 35 is pivotedby means of the pivot 4!: to the link 42, which is pivoted by meansof the pivot 3 to the plate I5. Rotation of the: shafts 54 and 35, therefore, will reciprocate. the plates I5 and 55 between definite end limits. The movement of these plates is controlled in such a mannerwthat the lower one of the two,. I:5, moves laterally inward practically to the end of its inward motion before the upper plate of the two, I6, moves laterally inward over the plate I5. As the plate I6 moves inward over the, plate I5, the plate I5 is. withdrawn at about the same; rate that the plate I5; moves. inward. In this arrangement, the plate I5 will fold over one side of the material about the plate I1, the plate it will fold over the other side of the material. about the other edge of the plate I! but over the material folded by the plate I5. This type of fold can be used to make a triple or a fourfolded sheet. If the material is of such a width that the plate I5 folds only one-half of the side section, so that the other half of the same side section remains on top of the plate I5 in its straight inward position, then as: the. plate. I5 turns over the edge. from the other side, a sheet with four folds will result. A sheet. with two, three, or four folds can be made with this. type of machine, as desired.

Means are provided by operations of a motion stop solenoid 55:" Figure 9 to stop suddenly the forward motion of the sheet while: the: folding occurs. When the sheetv is raised slightly by the action of the side. plates or when the tension of the center plate on the central conveyor belt is relieved in the folding, the. stop solenoid and its mechanism may" be dispensed with but forthe most part it is. a. useful mechanism- The mechanism is shown in Figs. 1-, 3, and 9. A cross support 93 extends across the frame. I. just before the roll 8-. This: cross support carries the stop solenoid 6.5- which, through its core I10, raises a bar I! I attached by an adjusting screw H2 to a link connected: to. the end ofthe; core. The bar HI carries two vertical rods I I3; and H4 which pass through vertical sleeves of holes in the beam or support 93, the rods carrying the cross clamp bar H5 which may have a soft cover, or rubber edge on its top which is brought against the underside of the cloth lying beneath the plate I'!, when the solenoid acts or isoperated. A pair of coiled springs in position about. the rods H3 and II 4 between collars I15 and sleeves Il'8 are slightly compressed by the operation of the solenoid and. return the bar quickly to its. normal inoperative position after the solenoid is deenergized. The solenoid; remains energized, however, during the whole folding operation and does not open until the switch 90 is momentarily opened as will be seen later.

The shafts 3 and are operated through a motor drive chain and clutch system. A driving motor 35 drives through a sprocket chain 4'! a reduction gear unit 48 which through a pair of beveled gears 49 and 50 rotates the upright shaft 5| on which another sprocket gear 52 is mounted, which drives through the chain 53 a second sprocket gear 5 5 which is pinioned to the shaft 55. The two shafts 5'! and 55, therefore, drive together continuously and rotate. the clutch collars or'sleeves 5% and- 5! respectively; to which the other halves of the clutch, 58 and 59, respectively, are connected in certain timed relations in the manner about, to: be; described. The lower clutch collars: 55 and 5! are pinned permanently to the drive shafts 5| and 55. The upper collar 58 carries a vertical pin 55 positioned in a key-way 5! (Figure 6). The pin 60 is recessed at the top to receive the spring. 62 which tends to force the pin downward against the detent or holding finger A, press fit sleeve d5 extends around the collar 58 and keeps the pin from falling out of the key-way. When thisdetent is released, the pin 6!} drops into the recess 64 in the lower clutch turns for a time with the drive shaft I.

4 and 5) operates to pull downward the shaft 61 (Fig. 4) by means of which the bell crank lever 66 is operated. The bell crank 1ever 66 bears against the arm 69, which forms a part of the lever 16 pivoted at II, which lever also carries the detent or finger 63 at its other end. Aspring I2 holds the end 69 of the lever I6 in contact with the bell crank lever 68 and also keeps the detent 63 in the collar or groove in the clutch 58. When the pin drops into the recess 64 in the collar 56, the shaft 34 will turn as stated above.

This shaft 34 carries a cam 13 which rotates with the shaft 34 and causes the operation of the arm 14 pivoted at 15 to a bracket or support I6 extending from a part of the frame. The arm 14 has linked toit at its other end a rod 11 freely pivoted to the bar or arm I4 in the pivot I8. This rod 'I'I extends laterally across the machine and operates at its further end an arm I9 somewhat similar to the arm I4. This arm I9 carries a projection 86 and is pivoted at its other end in the pivot BI and spring tensioned by the spring 82 so that the projection 86 normally seats in the groove 83 in the upper clutch'59 pinned to the shaft 35 by the pin 84. When the projection 86 of the arm I9 rides in the groove 83, the key or pin 65 (Fig. 5) is in its upper position and the shaft 35 does not turn. When, however, the cam I3 operating against the arm I4 rotates the lever 79 as viewed in Fig. 5 in a clockwise direction, the pin 85 will be forced downward by the spring 86 and the shaft 35 will turn. The operation of each shaft is usually set for a single revolution. The shaft 34 will turn according to the operation of the solenoid and the shaft 35 will turn at a certain time later depending upon the position of the cam 13. The cam I3 is positioned to accomplish the desired relation of operation in respect to the plates I5 and I6. When the plates operate through one revolution, the operating crank arms 36 and 3! will, of course, go through a single cycle, and so also the connecting links 39 and 42. In a normal three-fold operation, the plate I5 will move across the fixed plate I! about to the end at the time that the plate I 6 begins to move inward from its side, so that the plates I6 and I5 will be simultaneously moving to the right for the last part of the motion of the plate I5.

Nothing has been mentioned as yet with respect to the means by which the controls are operated. This may be accomplished through relay operating devices, either of the contact type or of the photo-electric type. In Fig. 1 there is shown a light source 2I, which casts a beam 81 against a photo electric cell device 88.

Before describing the rest of the machine which relates to transverse folding, the system of control for longitudinal folding will be described.

As the sheet intercepts the light source 81, the circuit to the photoelectric relay 88 is closed. Power I66 is normally supplied to the terminal panel I6I at the terminals I, 2', 4' and 'I, so that closing photorelay 88 places power across the terminal 6 which connects to the relay coil I62 and to the terminal 4', thus energizing the coil I62 causing the arm I63 to leave the contact I64 and connect to contact I65. This causes the relay coil l66 to be energized between 4' and I and 6 causes both contacts I68 and I69 to close. While contact I69 is closed, no current passes through this connection because the switch arm I63 is thrown to the right in contact with I65 and out of contact with I64 as long as the sheet intercepts the beam causing the coil I62 to hold the arm. All relays here are spring returned. The coil I66 is also maintained in a closed circuit through the contact I68, the terminal 3', the restoring switch 96 to the terminal I so that when the light beam 81 again shines on the photocell 36 this circuit still remains closed. The arm I68, however, immediately flies back because when the beam hits the cell 81, the current in coil I 62 is broken. The circuit is made from terminal 5 through the contact I 69, the contact I 64, the arm I63, the terminal I for the clutch solenoid 66 and the motion stop solenoid 66, which have one side connected to terminal 5' and the other side to terminal 4. The clutch solenoid 66 operates to commence the movements of the tables inward, the first table I5 by its motion causing the limit switch 9I to open, thus breaking the current of the clutch solenoid 66, but still keeping the circuit of the motion stop solenoid 66'. The tables complete this motion as has been explained, for the cycle after the pin 66 is permitted to drop; and at the end of the cycle the switch 9| is restored to a closed position but not before the restoring switch 66 has been momentarily opened de-energizing the coil I66, restoring contacts I68 and I69 to an open position. The switches are then in th positions indicated in Fig. 11, which is before the beginning of the cycle of operation for the longitudinal folding.

After the solenoid 66 has released the folded piece, the belt 24 draws the sheet toithe right (Figs. '7 and 8) to the transverse folding mechanism. A second roller I26, which may have a rubber cover, bears against the roller 26. This roller is journalled at each side of the machine to pivoted arms IZI pivoted at I22. A spring I23 tensions the roller I26 to the roller 26, and a chain drive I26 is so connected through sprocket gears I26 and I26 attached to the ends of the roller shafts that the roller I26 moves in opposite rotation to the roller 26. The roller I26 is covered by a plate I25 so that the sheet will first pass over the roller I26 without being drawn between the two rollers. After the sheet has gone beyond the roller I 26, it is picked up by the conveyor belt I 21, which is linked around the roller I28, positioned just beyond the rollers I26 and I29 near the end of the machine. The belt 1 I2! continues the travel of the sheet until the sheet hits the projecting arm I26 controlling the switch I36 which operates the solenoid I3I pulling the core I32 and the link I33 attached to the arm I36 which projects from the arm I36 pivoted at I35 on the same pivot as the bar I37. The arm I34 at its other end carries the thin plate I38. The arm I34 swings when the solenoid operates so that the plate I38 forces the sheet spanning the belt 24 and plate I 25 down between the rollers 26 and I20 folding the sheet as desired. The switch I36 may be moved along the bar or bracket I39 to any position in accordance with the fold desired.

Beneath the rolls 26 and I26 is another series of rolls I66 and MI, about which travels the conveyor belt I 42 moving in the direction of the arrow I43. The sheet which comes down between the rollers 26 and I26 drops on this conveyor belt and is carriedto the right (Fig. 8)

on. to; the plate I364. covering the top ofthe. roll I45. The sheet then comes. in contact withthe. belt, Me; traveling around rollers 55? and i 58 in the direction of the arrow I41, and is carried until it. trips the arm I48 of the switch M8 attached by arm l5El-to the bracket 1-5! which can be, adjusted; on. the support N32. The switch I69 operates a solenoid in back of the solenoid 13! (Fig. 8-) to pull down the rod I53 and operate the arm 1'54 carrying the plate M55. The sheet is forced between rollers Hi and M5, the latter of. which is pressed, against the former by the pivoted journal ar is? which isi-ndrawnto the left (Fig. 8) by spring I56. The sheet is again folded by passing between the rolls MI and i451 and is deposited upon conveyor belt I59, which; travels around rollers ISll and IS! in the direction of the arrow it$2.. At the end of its travel? thev sheet, now twice. transversely folded, is carriedbeneath the nip roll H53 which is preferably rubber covered and is pressed against the belt 55% by the spring i455 which draws the pivoted bracket I64: inwhich the nip rolls are journ'alled:

The folded sheet is deposited thereafter on the automatic stacker 566- shown at the extreme right: in Fig. 8.

The; operation of the switch I49 also operates the stacker mechanism, so that on each passage ofa sheet the stacker mechanism will operate but to stack the sheet which has previously operated the switch. That is, there is a lapse between the time when the switch operates until the; sheet operating: it reaches the stacker so that the following sheet causes the stacking of the sheet previously deposited.

- The stacker comprises a platform I76 which is raised and lowered in one cycle of operation by a crankarm HI and link H2 when the clutch mechanismv H3 is operated by the solenoid H4 and core IT'S. The solenoid is operated by the switch M3 and the operation of the clutch by it is. just the same as that of the clutch previously described in theoperation of the longitudinal fold plates.

The platform H0 is therefore. raised by the shaft. H2. when the operating cycle begins.

Mounted over the platform but pivoted at the side. are a group of uniformly spaced bell cranklike levers. H3. These are thin arms which are aligned with slots in the platform so the platform can be raised. above the arms. The bell crank levers are spring tensioned, downward so that the arms are normally in a horizontal position.

Ihe sheet deposited on the platform covers the slots so that as the platform, comes to the level of the arms of the lever N3, the arms are raised until they clear the platform and drop back to a horizontal position. They are therefore under the slots on the platform in this position so that when the platform drops back, the sheet on it and oth'erswhich were on the arms are deposited on the arms, with the last sheet at the bottom of the stack.

, In Fig. 12 there is shown a mechanism which may be used in connection with the machine. This includes a pair of feed rollers We and "H, which are held in contact by means of a spring 182. These feed rollers take the sheet from the conveyor 2 3 after it has been folded and send it up an inclined guide I83 to a pair of ironing rollers 8d and lat, which are held together in compression by the spring !86. The roller I85 may be a steam roller or heated by other means if desired. The ironed sheet leaves the ironer 8 over the: guide I:8:1- and is. againdeposited on the belt 24...

I claim:

1. Means for effecting parallel folds of sheetv material comprising a stationary central plate and side plates: all having cooperating straight edges which are. disposed substantially mutually parallel, the plates. occupying parallel planes with the side plates being insubstantially the samepla-ne and the central plate in a plane below that of: the side plate, means for feeding and directing the sheet material so that a portion thereof underlies. the central plate and other portions overlie the side plates and means for moving the side plates within their respective planes laterally in phased; reciprocal motion over the central plate and returning them to their normal side positions for effecting a lengthwise fold of the sheet material.

2. Means. for effecting parallel folds of sheet material comprising a stationary central plate and side plates, the: plates occupying parallel planes with the side plates being in substantially the same plane and the central plate in a plane, below that of theside plates, means for feeding and directing the sheetmaterial so that a portion' thereof will underlie the central plate and other portions overlie the side plates, the central and side plates having edges extending in the direction of the feed ofthe sheet material,

and means for moving said side plates in phased reciprocal motion within their respective planes over a portion of the central. plate and returning; them to their side positions.

3. Means for. effecting parallel folds of sheet material comprising a stationary central plate and side plates positioned substantially parallel to one another andthecentral plate but at slightly different levels above the central plate, means for feeding and directing the sheet ma-. terial so that a portion, thereof willunderlie the central plate and: other portions overlie the side plates, means for alternately moving the side plates: laterally within their respective planes over a portion of the central plate and returning them to their side positions for effecting a length wise fold of the sheet material.

4. Means for effecting parallel folds of sheet material comprising" a, stationary central plate and side'plates all having cooperating straight edges, said plates being positioned substantially parallel to one another but with the side plates at slightly different levels above the central plate, means for feeding and directing the sheet material so that a portion thereof underlies the returning them to their normal positions, the

movement of the upper side plate inwardly approximately following the movement of the lower side plateoutwardly of the central plate.

5. Means for effecting parallel folds of sheet material comprising a stationary central plate and side plates all having cooperating straight edges which are disposed mutually parallel, means for feeding and directing the sheet material so that a portion thereof underlies the central plate and other portions overlie the side plates, the plates occupying parallel planes with the side plates being in substantially the same plane and the central plate in a plane below that of the side plates, means for moving the side plates within their respective planes in phased reciprocal motion over side portions of the central plate and returning them to their side positions and means for holding the sheet in the region of the central plate during the moving of the side plates.

6. Means for effecting parallel folds of sheet material comprising a stationary central plate and side plates, the plates occupying parallel planes with the side plates being in substantially the same plane and the central plate in a plane below that of the side plates, means for feeding and directing the sheet material so that a portion thereof will underlie the central plate and other portions overlie the side plates, the central and side plates having edges extending in the direction of the feed of the sheet material and means for moving the side plates within their respective planes laterally in phased reciprocal motion over side portions of the central plate and returning them to their side positions and means for clamping the sheet to the central plate during the moving of the side plates.

7. Means for effecting parallel folds of sheet material comprising a conveyor belt system having side conveyors and fixed elevating fingers associated therewith and. a central nonoonveyor region, a central plate and side plates at a level higher than said central plate, said central and side plates being positioned as extensions of the nonoonveyor region and the side conveyors respectively with said elevating fingers extending from said side conveyors upwards to said side plates whereby the sheet material will be raised at the sides by the elevating fingers over the side plates and in the center remain under the central plate, and means for moving the side plates laterally in phased reciprocal motion over the central plate and returning them to their normal side position for effecting a lengthwise fold of the sheet material, said central and side plates all having cooperating straight edges which are disposed mutually parallel.

8. Means for effecting parallel folds of sheet material comprising a conveyor belt system having side conveyors and fixed elevating fingers associated therewith and a central nonoonveyor region, a central plate and side plates ata level higher than said central plate, said central and side plates being positioned'as extensions of the nonoonveyor region and the side conveyors respectively with said elevating fingers extending from said side conveyors upwards to said: side plates whereby the sheet material will be raised at the sides by the elevating fingers over the side plates and in the center remain under the central plate, one of said side plates being at a level lower than the other side plate and means for alternately moving first the lower of the side plates and then the upper laterally from the side to a position over the central plate and then returning them to their normal side position, the movement of the upper plate inward approximately following the movement of the lower plate outward of the central plate, said central and side-plates all having cooperating straight edges which are disposed mutually parallel.

9. Means for effecting parallel folds of sheet material comprising a conveyor belt system having side conveyors and fixed elevating fingers associated therewith and a central nonoonveyor region, a central plate and side plates at a level higher than said central plate, said central and side plates being positioned as extensions of the nonoonveyor region and the side conveyors respectively with said elevating fingers extending from said side conveyors upwards to said side plates whereby the sheet material will be raised at the sides by the elevating fingers over the side plates and in the center remain under the central plate, and means for moving the side plates laterally in phased reciprocal motion over the central plate and returning them to their normal side position for effecting a lengthwise fold of the sheet material, and a conveyor belt positioned beneath the central plate and adapted to contact with the material thereunder to moving the sheet after folding from said plate, said central and side plates all having cooperating straight edges which are disposed mutually parallel.

19. Means for effecting parallel folds of sheet material comprising a stationary central plate and side plates the plates occupying parallel planes with the side plates being in substantially the same planes and the central plate being below that of the side plates, means for feeding and directing the sheet material so that a portion thereof will underlie the central plate and other portions overlie the side plates, the central and side plates having edges extending in the direction of feed of the sheet material, means for moving the side plates laterally in phased reciprocal motion over the central plate and returning them to their normal side position for effecting a lengthwise fold of the sheet material and control means operated when the sheet material has reached the desired position for beginning the movement of said side plates.

11. Means for effecting parallel folds of sheet material comprising a fixed central plate and side plates all having cooperating straight edges which are disposed mutually parallel, means for feeding the sheet material under the central plate and over the side plates, means for moving the side plates laterally in phased reciprocal motion over the central plate and returning them to their normal side position for eifecting a lengthwise fold of the sheet material, electrical control means and clutch elements operated thereby, an electrical power means adapted to be coupled through said clutch for operating the means for moving said plates, and means for operating said electrical control means when the sheet material has reached the desired position for operating the clutch to couple said electrical power means for beginning the movement of said plates.

12. Means for effecting parallel folds of sheet material comprising a fixed central plate and side plates all having cooperating straight edges which are disposed mutually parallel, means for feeding the sheet material under the central plate and over the side plates, means for moving the side plates laterally in phased reciprocal motion over the central plate and returning them to their normal side position for effecting a lengthwise fold of the sheet material, a photo-, electric cell and beam arranged to be interrupted by the sheet material as it begins to pass in the region of said central and side plates, and means controlled and timed after the interruption has ceased for beginning said move-. ment of said side plates when the sheet material has come into a position so that a portion thereof will underlie the central plate and other portions overlie the side plates.

13. Means for effecting parallel folds of sheet material comprising a fixed central plate and acetates side plates all having cooperating straight edges which are disposed mutually parallel, means for feeding and directing the sheet material so that a portion thereof underlies the central plate and other portions overlie the side plates the :plates occupying parallel planes with the side plates substantially the same plane and the central plate in a plane below that of the side plates, the central and side plates having edges extending in the direction of the feed of the sheet material, and means for moving the side plates within their respective planes laterally in phased reciprocal motion over the central plate and re turning them 'to their normal side position for effecting a lengthwise fold of the sheet material, including a pair iof vertical drive shafts having an operating clutch connected therewith posttioned one under each of said plates, a crank arm and link for each of said side plates operatively connected thereto and to said drive shafts, and control means operative when the sheet is in the desired position for operatingsaid clutch for moving said side plates.

14. Means for effecting parallel folds of "sheet material comprising a conveyor belt system having side conveyors and fixed elevating fingers associated therewith and a central nonconveyor region, a central plate and side plates at a level higher than said central plate, said central and side plates being positioned as extensions of the nonconveyor region and the side conveyors respectively with said elevating fingers extending from said side conveyors upwards to said side plates whereby the sheet material will be raised at the sides by the elevating fingers over the side plates and in the center remain under the central plate, and means for moving the side plates laterally in phased reciprocal motion over the central plate and returning them to their normal side position for effecting a lengthwise fold of the sheet material, including a pair of vertical drive shafts having an operating clutch connected therewith positioned -'one under each of said plates, a crank arm and link for each of said side plates operatively connected thereto and to said drive shafts and control means operative when "the sheet has reached the desired position for operating said clutches for moving said side plates, said central and side plates all having cooperating straight edges which are dis-'- posed mutually parallel.

15. Means for efiecting parallel folds of sheet material comprising a conveyor belt system having side conveyors and fixed elevating fingers associated therewith and a central nonconveyor region, a central plate and side plates at a level higher than said central plate, said central and side plates being positioned as extensions of the nonconveyor region and the side conveyors respectively with said elevating fingers extending from said side conveyors upwards to said side plates means mounting said side plates in planes just above one another and above the central plate, including a pair of supporting rods extending transversely beneath the plates having sliding sleeves thereon and means mounting said side plates to said sleeves at the outer side region of said plates whereby said side plates may be moved in positions over one another and above the central plate without interference, and means for moving the side plates laterally in phased reciprocal motion 'over the central piate and returning them to their normal side positions for effecting a lengthwise fold of the sheet material, said 'central and side plates all having 12 cooperating straight edges which are disposed mutually parallel.

16. Means for effecting parallel folds of sheet material comprising a conveyor belt system having side conveyors and fixed elevating .fingers associated therewith and a central nonconveyor region, a central plate and side plates at a level higher than said central plate, said central and side plates being positioned as extensions of the nonconveyor region and the side conveyors respectively with said elevating fingers extending from said side conveyors upwards to said side plates a frame extending over "and across the conveyor belt, means flexibly supporting said central plate at the forward end from "said'frame, a second :conveyor belt positioned just beneath said central plate on which the other end of said central plate rests lightly, means .for moving the side plates laterally in phased reciprocal motion over the central plate and returning them to their normal :side position for effecting a lengthwise fold of the sheet material, said second conveyor belt acting to carry said folded sheet on said central plate after the folding, said :central and side plates all having cooperating straight edges which :are disposed mutually "parallel.

'17. Means for eflect-ing a lengthwise fold in a sheet material comprising a movable :plate and a stationary plate each occupying parallel planes side by side and the movable plate being at a level above that of the level of the stationary plate, means for feeding and directing the sheet material in a lengthwise direction so that a por tion thereof will underlie "the stationary plate and the other portion will overlie the movable plate and means for YHIGV-iflg the movable plate withinitszrespective :pla-ne over a portion-of the stationary :plate and returning the same to its side position whereby .a lengthwise fold of the sheet material will be made.

18; Means for effecting zpa'rallel folds 'of sheet material comprising =a-fixed central plate and side plates, the plates :o'ccupying parallel planes with the aside plates being :in substantially the same plane and the central plate in a plane below that :of the side fplates, means iorzieeding and directing the sheet-material so that a .por tion thereof will zunderlie the central plate and other portions overli'e the side-plates the central and side plates shaving aedges extending .in the direction "of the feed of the sheet material, means for moving the 'side plateslaterally in phased reci preeal motion oyer the .central plate and returning them to "their norinal :side position for effecting a 'q'en'gthwise I fold 'ef the sheet material, and a conveyor positioned beneath the central plate and in contact therewith .for continuing the forward inevemeiit of the sheet after the "lengthwise folds have been made.

19. Means for efi'ecti ng parallel raids or sheet material comprising aconveyor belt system, a fixed central plateand side plates positioned above the level "of "said central plate and ser-vi r-ig as a continuation of said conveyor belt system with a plurality of elevating fingers for conducting the materialbversa'id side plates, said sheet material normally progressing under said central plate, means for moving the side plates laterally in phased reciprocal motion ever the central plate and ret'urn ing them to their normal side "positions 'for eifectinga lengthwise fold of the sheet material, and means for conveying the sheet material 'oii bi said central plate.

20. Means for effecting parallel ifolds of sheet material comprising a fixed central plate and 13 side plates, the plates occupying parallel planes with the side plates being in substantially the same plane and the central plate in a plane below that of the side plates means for feeding and directing the sheet material so that a portion thereof will underlie the central plate and other portions overlie the side plates the central and side plates having edges extending in the direction of the feed of the sheet material, means for moving the side plates laterally in phased reciprocal motion over the central plate and returning them to their normal side position for effecting a lengthwise fold of the sheet material, and means for conveying the folded sheet away from the central plate.

ROBERT L. SJOSTROM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Number 15 457,159 

